Empirical Parameters of the Polarity of Solvents

Reichardt, C.

doi:10.1002/anie.196500291

Cited by 479 publications

(181 citation statements)

References 110 publications

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“…Various solvent parameters are shown in Table V. There is an approximately linear relationship between the reaction constants for all the solvents, except dimethyl sulfoxide, and the reciprocal of the dielectric constant (14), as shown in Data exist for the closely related solvent parameters ET and S (14) for the solvents under study. However, these do not linearly correlate the change in the reaction constants.…”

Section: Ddm Reactiorzmentioning

confidence: 73%

The transmission of polar effects. Part V. The kinetics of esterification with diazodiphenylmethane and the ionization of substituted acetic and propionic acids in several solvents

Bowden¹,

Hardy²,

Parkin³

1968

Can. J. Chem.

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The rate coefficients for the reaction with diazodiphenylmethane in methanol, ethanol, isopropyl alcohol, t-butyl alcohol, 2-methoxyethanol, 2-n-butoxyethanol, dimethyl sulfoxide, ethyl acetate, and toluene at 30" and the pK, values in water, 50% ethanol-water, and 80% 2-methoxyethanol-water of 18 substituted acetic and propionic acids have been determined. A further 14 acids have been studied to a more limited extent. The effect of substitution has been estimated by linear free energy relations. The reaction constants for the ionization reaction are almost independent of the medium. This is interpreted as being due to the field effect of the proximate polar substituents passing through the molecular cavity almost alone. The occurrence of steric inhibition of solvation causing acid weakening for bulky multisubstitution is confirmed. The reaction constants for the esterification reaction are affected by the solvent. This is attributed to dependence on solvation of the transition state.Canadian Journal of Chemistry, 46, 2929 (1968) IntroductionAs part of our examination of the mode of the transmission of polar effects, it was considered important that transmission in aliphatic systems and their dependence on the medium should be studied. Suitable reactions were considered to be the esterification of carboxylic acids with diazodiphenylmethane (DDM) and their ionization. The system chosen for this study was a series of singly substituted acetic and 3-substituted propionic acids, together with a number of more highly substituted acids. The intention was to obtain a comprehensive series of results for the esterification and ionization reactions for this model system in order to be able to discuss the influence of the substituents on reactivity in aliphatic systems.Taft in his pioneering studies (1) made a distinct advance in understanding polar substituent effects in aliphatic systems. The aliphatic polar substituent constants, a*, which had been separated from the accompanying steric effects in ester hydrolysis, were found to correlate, among other reactions, the ionization of aliphatic carboxylic acids in water at 25" (1) and the esterification of the acids with DDM in ethanol at 25" (2). Hoefelmeyer and Hancock (3) and Bowden, Chapman, and Shorter (4) have extended these correlations to the esterification of aliphatic

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Section: Ddm Reactiorzmentioning

confidence: 73%

The transmission of polar effects. Part V. The kinetics of esterification with diazodiphenylmethane and the ionization of substituted acetic and propionic acids in several solvents

Bowden¹,

Hardy²,

Parkin³

1968

Can. J. Chem.

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“…The most common empirical solvent polarity scale relies on the solvatochromic behavior of various dyes in different solvent systems (15)(16)(17)(18). In terms of solvent strength and selectivity, this method was also used to classify single-and mixed-solvent LC systems (20).…”

Section: Description and Propertiesmentioning

confidence: 99%

Ionic Liquids in Analytical Chemistry

Anderson¹,

Armstrong²,

Wei³

2006

Anal. Chem.

491

326

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oom-temperature ionic liquids (RTILs), also known as liquid organic, molten, or fused salts, are a class of nonmolecular ionic solvents with low melting points. The accepted definition of an RTIL is any salt that has a melting point lower than ambient temperature (1). However, "ionic liquid" (IL) is often applied to any compound that has a melting point <100°C. Most common RTILs are composed of unsymmetrically substituted nitrogen-containing cations (e.g., imidazole, pyrrolidine, pyridine) with inorganic anions (e.g., Cl -, PF 6 -, BF 4 -). ILs are also interesting because of their other useful and intriguing physicochemical properties. Wilkes et al. first reported ambient-temperature ILs based on the 1-alkyl-3-methylimidazolium cation in 1982 (2). Since then, many ILs containing a variety of cations and anions of different sizes have been synthesized to provide specific characteristics.Over the past few years, research and applications of ILs have expanded tremendously. The initial impetuses for this expansion were organic synthesis and the growth of green chemistry. In this article, we will give an overview of the structure and properties of ILs and describe their expanding use in various applications in separations and chromatography, MS, spectroscopy, and electrochemistry. Description and propertiesILs have negligible vapor pressures at room temperature, possess a wide range of viscosities, can be custom-synthesized to be miscible or immiscible, often have high stability, and are capable of un-

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“…The early proposed definition of polarity as simply the solvent´s overall solvation capability (or solvation power) [19,37] was officially accepted by the IUPAC committee [38]. In other words, different types of molecular association involving the spin probe and solvent molecules such as hydrogen bonding, van der Waals interaction or any type of electron redistribution in the vicinity of the N-O moiety are all, included in the polarity definition.…”

Section: Resultsmentioning

confidence: 99%

Application of Electron Paramagnetic Resonance Spectroscopy for Validation of the Novel (AN+DN) Solvent Polarity Scale

Malavolta

Poletti

Silva

et al. 2008

IJMS

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Abstract:Based on solvation studies of polymers, the sum (1:1) of the electron acceptor (AN) and electron donor (DN) values of solvents has been proposed as an alternative polarity scale. To test this, the electron paramagnetic resonance isotropic hyperfine splitting constant, a parameter known to be dependent on the polarity/proticity of the medium, was correlated with the (AN+DN) term using three paramagnetic probes. The linear regression coefficient calculated for 15 different solvents was approximately 0.9, quite similar to those of other well-known polarity parameters, attesting to the validity of the (AN+DN) term as a novel "two-parameter" solvent polarity scale.

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Empirical Parameters of the Polarity of Solvents

Cited by 479 publications

References 110 publications

The transmission of polar effects. Part V. The kinetics of esterification with diazodiphenylmethane and the ionization of substituted acetic and propionic acids in several solvents

The transmission of polar effects. Part V. The kinetics of esterification with diazodiphenylmethane and the ionization of substituted acetic and propionic acids in several solvents

Ionic Liquids in Analytical Chemistry

Application of Electron Paramagnetic Resonance Spectroscopy for Validation of the Novel (AN+DN) Solvent Polarity Scale

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